Hubble Essentials: Quick Facts

Hubble is nearly the size of a large school bus — but it can fit inside a space shuttle cargo bay. Enlarge image

Hubble's two mirrors were ground so that they do not deviate from a perfect curve by more than 1/800,000th of an inch. If Hubble's primary mirror were scaled up to the diameter of the Earth, the biggest bump would be only six inches tall. Enlarge image

Hubble's Name
NASA named the world's first large, space-based optical telescope after American astronomer Edwin P. Hubble (1889—1953). Dr. Hubble confirmed an "expanding" universe, which provided the foundation for the Big Bang theory.

Pointing Accuracy
In order to take images of distant, faint objects, Hubble must be extremely steady and accurate. The telescope is able to lock onto a target without deviating more than 7/1000th of an arcsecond, or about the width of a human hair seen at a distance of 1 mile.